DESCRIPTION (Applicant's Description): The goal of this proposal is to obtain support for our postdoctoral training program in molecular imaging research. Funds are requested to support four postdoctoral trainees per year. Our program emphasizes the education of basic (Ph.D.) and clinical (M.D. or M.D./Ph.D.) scientists in the principles and applications of molecular techniques to answer basic science questions through in vivo imaging. Overall, we believe the development, validation, and application of such novel imaging techniques (e.g. receptor mapping, imaging of gene delivery and gene expression, imaging of cell trafficking in vivo, 3D imaging in developmental biology) should further enhance our understanding of disease mechanisms and go hand in hand with the development of molecular medicine. The program consists of didactic lectures, laboratory exercises and individual research projects. Trainees that successfully complete the program are excellent candidates for academic positions. The primary faculty consists of 19 M.D./Ph.D. and/or Ph.D. scientists with extensive experience in basic research and in pre and postdoctoral education. The faculty has over 35 extramural research grants including over 20 R01, 6 Program Project Grants, 5 Center Grants and 15 NCI grants that directly address issues of cancer diagnosis and therapy using novel imaging approaches. The faculty has successfully supervised over 300 pre- and postdoctoral fellows in various aspects of basic and clinical research. Most recently, the program has been enhanced by the addition of several new faculty members, the acquisition of funded research in a broad range of areas and the availability of state-of-the-art facilities (MGH Center for Molecular Imaging Research). These factors have increased the educational and research opportunities for trainees. We have also developed successful programs in minority recruitment, scientific integrity and cancer related training and research. We feel strongly that, with our current faculty, facilities, scope of supported research, and past accomplishments, we can achieve our stated goal of providing highly qualified M.D. and Ph.D. scientists for the biomedical research community.